1. Field of the Invention
The present invention relates in general to an apparatus for folding margins of flexible materials and, more particularly, to an air enhanced hem former to be used with a sewing machine.
2. Description of the Prior Art
Materials used in the manufacture of clothing, such as cotton, polyester, rayon and other cloth materials invariably have an end, or margin. The margin is typically folded and sewn to form a hem. The hem provides strength to the clothing, prevents fraying, evens the length of the margin, and allows for subsequent length adjustments. Hems are formed in a variety of ways.
One common method of forming a hem is to manually fold the margin back onto the material and then hand or machine stitch the margin to the material. However, this method is very time consuming and requires skilled operators. Another common method of forming a hem uses a thin plate to fold the margin around and then back onto the material. Once the margin is so positioned, an operator can hand or machine stitch the margin to the material. However, it is often difficult, if not impossible, for an operator to quickly and accurately fold the margin around the plate and into position for stitching.
To overcome the problems relating to quickly and accurately folding the margin into a proper stitching position, streams of compressed air have been used. One such design is illustrated by U.S. Pat. No. 3,631,826 issued to Morgan. Morgan apparently discloses a hem former in which the path traveled by the margin during sewing uses an airflow outlet formed below the margin and below a support plate, with the airflow perpendicular thereto. A deflector 44, 58 perpendicularly deflects the airflow toward the margin so that the margin is carried by the airstream toward the sewing needle whereas other airstreams guide the margin through multiple folds for stitching parallel to the margin. However, this airstream design causes the margin to flutter when in the airstream and inefficiently directs the margin toward the stitching needle because of the 90.degree. angle change which the airstream undergoes. Further, margin positioning is not maintained during stitching.
Another air enhanced hem former design is illustrated by U.S. Pat. No. 5,441,004 issued to Bottoms. Bottoms apparently discloses an airflow outlet that is angularly formed toward the rear bottom portion of a support plate 22. The margin is manually urged across the plate, then vertically downward below the plate, and only then does the margin 13 enter the airstream. Thus, an operator must manually urge the material across the plate and then vertically downward over the edge of the pate before the margin enters the airstream 37. Only after this manual urging can the airstream fold and direct the margin into position for stitching. However, manual urging of the margin can cause the margin to snag, bunch, or misalign before entering into the airstream.
Additionally, the prior art does not address the problem of maintaining the margin in a proper position after being directed by the airstream. Thus, after the airstream folds and directs the margin but before the stitching process is completed, the margin can become mispositioned. This results in improperly stitched margins.
There is thus a need for a hem former which urges the material toward the needle, directs the material to a proper sewing position and maintains this proper sewing position until the needle has stitched the hem.